Today: A quartet of Silicon Valley acquisitions can’t help push Wall Street higher, as declines from VMware and future ex-customer eBay combine with fears of more European economic issues to push stocks down.

Merger Monday was in full effect for Silicon Valley, with news of four tech titans purchasing smaller companies as local firms seek uses for their cash in a changing tech environment.

The first move actually happened during the weekend, when Apple (AAPL) confirmed that it purchased Palo Alto startup WiFiSlam, a move that could be aimed at upgrades for the much derided Apple Maps venture. The Wall Street Journal originally reported the acquisition, citing an anonymous source with a $20 million price tag. Apple confirmed, but did not disclose a price or any plans for the engineers and technology it acquired.

WiFiSlam focuses on mapping interiors, such as the layouts of malls and other large areas, using Wi-Fi signals to help direct users. The 2-year-old company’s technology could help Apple Maps upgrade its Apple Maps app, which was so bad upon launch that CEO Tim Cook apologized to customers.

A more frequent acquirer than Apple, Yahoo (YHOO) continued to build its mobile division through the purchase of other companies Monday, announcing that it had picked up Summly, a news-aggregation app developed by a British teenager. AllThingsD reported that Yahoo paid $30 million for the app and its founder, Nick D’Aloisio, who will stay in London to continue his schooling while being the Sunnyvale Internet company’s youngest employee.

“What I am excited about with Yahoo is under the new leadership of Marissa Mayer, it’s a classic Internet company that has such a big opportunity,” D’Aloisio told Reuters in an interview Monday.

Mayer has focused on Yahoo’s mobile efforts since taking over the company last year, with the former Googler acquiring a company founded by former co-workers to form the backbone of a mobile division and then acquiring other small mobile companies to build the mobile talent base. Yahoo has also redesigned some of its signature mobile apps while honing its list down to a manageable, targeted list offerings.

A Yahoo blog post confirming the transaction, but not the reported price, noted that Summly is “a mobile product company founded with a vision to simplify the way we get information, making it faster, easier and more concise,” and that Yahoo sees mobile devices as being “at the center of how we engage with the people, experiences and interests we love.”

Cisco (CSCO) — which has a history of acquiring plenty of companies as it leads the networking sector — continued its recent focus on foreign software companies, purchasing Austrian software firm SolveDirect, which helps companies manage their cloud services. CEO John Chambers has said that he is beefing up Cisco’s software holdings through acquisitions in order to make sure Cisco’s products can run the hardware it sells to enterprise customers.

Chambers has also said that the San Jose company will acquire only foreign companies until the United States allows it to bring home money collected overseas at a lower tax rate than what is currently charged. Monday’s purchase follows the $475 million acquisition of Israeli networking software company Intucell in January, showing that Chambers is living up to his word.

Oracle (ORCL), a serial acquirer like Cisco, also continued a recent trend with its Monday announcement, picking up private North Carolina telecommunications software company Tekelec for an undisclosed sum. The move follows Oracle’s February purchase of Acme Packet, another telecom-related company that was the Redwood City’s largest acquisition since Sun Microsystems in 2010.

Oracle’s purchase of Acme Packet showed its desire to forcefully target the telecoms industry for enterprise hardware and software, a challenge to Cisco, which wants the same business and purchased Intucell for that reason. Oracle CEO said last month that Oracle’s “ambition is to be the primary technology provider to the telecommunications industry,” according to The Wall Street Journal.

Oracle said in its announcement that it would look to combine Tekelec with Acme Packet’s technology for a full-service telecom offering. While no price was disclosed, the Journal reported that Tekelec was taken private for about $761 million in 2011.

Apple, Yahoo and Cisco recorded slight gains Monday in the first trading since their respective deals, while Oracle continued to spiral after its disappoint earnings report last week. Apple increased 0.4 percent to $463.58; Yahoo gained 0.5 percent to hit another new 52-week high at $23.38; Cisco added 0.5 percent to $20.85; and Oracle dropped 2.3 percent to close at $31.25.

VMware takes a tumble after eBay moves to OpenStack, Tesla gains

Overall, Silicon Valley had a rough day on Wall Street, with the SV150 index of the area’s largest tech companies declining 0.5 percent as VMware took a dive after losing a big customer.

eBay (EBAY) and its PayPal business will replace VMware on its 80,000 servers with open-source cloud management system OpenStack, an OpenStack board member told BusinessInsider. The open-source alternative to VMware’s popular cloud offering has already received prominent backers like IBM, which adopted OpenStack in a move that many felt made the open-source system the standard platform.

Palo Alto-based VMware, which has yet to fully recover from a late-January swoon preceded by the announcement of layoffs and disappointing earnings results, dropped 5 percent Monday to close at $76.50.

eBay didn’t profit immediately from the move, dropping 3.7 percent after the U.S. Senate voted in favor of a nationwide online sales tax in a vote that happened after markets closed Friday afternoon.

On the positive side, Tesla gained 2.5 percent after CEO Elon Musk said on Twitter that he would have an important announcement Thursday, which may have made some investors shudder after the battle between the tech entrepreneur and The New York Times earlier this year. Another Musk company, SolarCity, also had a strong day with a 1.9 percent gain; Musk is chairman and a major investor in the Peninsula solar installer.

Cyrpus situation resolved, but fears still hurt stocks

Stocks fell overall Monday, after the Cyprus situation was finally defused, but in a way that left investors worrying about the effect on the greater European economy.

All three major U.S. stock indexes declined, as investors showed concern that the Cyprus situation was just the first domino to fall in a weakened European economy. Stocks moved higher, including a near-record-high for the Standard & Poor’s 500, until a Eurozone official backed off comments calling the solution in Cyrpus a template for other countries, instead saying they would be handled on a case-by-case basis.

“There was certainly a sigh of relief that a deal was reached, but there are still growing concerns that more work needs to be done,” Jack Ablin, the chief investment officer of BMO Private Bank, told Reuters.

And the widely watched Standard & Poor’s 500 index: Down 5.2, or 0.33 percent, to 1,551.69

Check in weekday afternoons for the 60-Second Business Break, a summary of news from Mercury News staff writers, The Associated Press, Bloomberg News and other wire services. Contact Jeremy C. Owens at 408-920-5876; follow him at Twitter.com/mercbizbreak.

Otto Warmbier was arrested in January 2016 at the end of a brief tourist visit to North Korea. He had been medically evacuated and was being treated at the University of Cincinnati Medical Center when he died at age 22.